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Chapter 1
Essentials of
Geography
Robert W. Christopherson
Charlie Thomsen
• The science that studies the relationships
among
– natural systems
– geographic areas
– society
– cultural activities
– and the interdependence of all of these over
space
Geography Is
• PG: studies the physical elements and
processes that make up the natural environment
• HG: studies patterns and processes that make up the human environment
No strict boundaries, human environment have to exist on the Earth
surface, and human activities modify the natural environment.
Physical/Human Geography
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Figure 1.2
Geographer’s Perspectives of the World
Location Matters
Real-world Relationships
Horizontal connection among places
Importance of Scale (both in time and space)
Scientific Method
Figure FS 1.1.1
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• Systems theory
• Open systems
• Closed systems
• System feedback
• System equilibrium
Earth Systems Concepts
• A System is any ordered, interrelated set
of entities and their attributes, linked by flows of energy and matter, as distinct
from the surrounding environment out side the system:
e.g. a car, a house, a pound, a watershed, a hurricane, the ocean, the earth, …
Earth Systems Concepts
• Reservoir/Stock/the state variable: a repository where matter/energy is stored over time.
• Processes (flows of energy/matter): the activities in the system that determines the content of the reservoir over time.
• Parameters: which regulate the rate of change in the processes.
• Relationships: connections among the components of system.
System Components
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System Components: ExamplesA pound as a system:
Stock:
flows:
parameters:
relationship:
Timber resources in a forest farm as a system:
Stock:
Flows:
parameters:
relationship:
1. Open/Closed Systems
2. System Feedbacks
Positive Feedback: unstable
Negative Feedback: stable
3. System Status:
Growth/Decline
Steady-State
System Properties
Figure 1.3
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Open Systems
Figure 1.4
Systems in Steady State
Figure 1.5
01_0 5. JPG
Steady-state is not static, but dynamic. A steady-state system can withstand
certainly level of disturbance and the system can regain its steady-state. After a threshold (tipping point), the system will be permanently displaced
and regain new steady-state.
Tipping Point Example
Figure 1.5
Harlequin Frog:
Monteverde Cloud Forest Reserve, Costa Rica
Moist and porous skin: fungus penetration
Global Warming
More Water in the air
More Clouds over Mountains
Increase nighttime minimum T
Decrease daytime maximum T
Chytrid fungus:
ideal T: 17~25oCstop grow: 28oC
dies: 30oC
1986-2006:
67% of the 110 known
species of Harlequin frog extinct.
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Earth’s Four Spheres
Figure 1.8
Earth System Characteristics
Figure 1.8
1. A dynamic evolving system: energy and matter are constantly being transferred and changing in form.
2. An open system with respect to energy.
3. A nearly steady-state system in energy.
4. A almost closed system with respect to matterexception: air molecules escape earth gravity to leave the Earth system, and meteorites from outer space.
Earth Dimensions
Figure 1.9
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Measuring Earth in 247 B.C. by
Eratosthenes
Figure 1.10
1 statium=185 m,
5000*185m*50=46,250km
• Latitude
• Longitude
• Great circles
• Prime Meridian and standard time
Location and Time on Earth
Latitude/Parallel
Figure 1.11
Latitude: angles
Parallels: the line
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Latitudinal Geographic Zones
Figure 1.12
Longitude
Figure 1.13
Time
Greenwich Mean Time (GMT): Local time for the prime meridian.
Eastern Standard Time: Local time for the meridian of 75oW(Central Time, Mountain Time, Pacific Time, Alaska Time)
Beijing time: Local time for the meridian of 120oE
Local Time: Local noon: The instant that the local meridian swipe across the sun
is defined as the local noon.
For scientific calculation, we often need local time
e.g. how high the sun is in the sky?
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Prime Meridian and Standard Time
Figure 1.17
• Map –A graphic depiction on a flat medium of all or part of a geographic realm in which real world features have been replaced with symbols in their correct spatial location at a reduced scale.
• Scale – ratio of map units to ground units
Large/small scale
fine/coarse scale
• Projection – process of transforming points on 3D spherical Earth Surface to 2D flat medium (e.g. paper).
Maps, Scales, and Projections
Figure 1.21
Classes of
Map
Projections
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• GIS is a computer system that allows visualization, storage, analysis and update of geographic data (spatial and attribute data)
• GIS can create digital maps that contain multiple data layers:
– Physical features (rivers, forests, topographic
– Cultural features (populations, economic, social…)
• Layers can be added to create composite overlay
• Many modern environmental problems need many layers of Geographic data and Geographers play pivotal roles in help us understand or find solutions or mitigate these problems.
Geographic Information Systems (GIS)
GIS System Model
Figure 1.29